Spark plug



Jan. 16, 1934. l.. J. JoNEs 1,943,481

SPARK PLUG Filed July 1'7, 1931 2 Sheets-Sheet l r-/ 3 Inventor 5. f/vew /Illorney Jan. 16, 1934. l.. J. JONES 1,943,481

SPARK PLUG Filed July 17, 1931 2 Sheets-Sheet 2 Inventor cf, (f/Vey Aso Patented Jan. 16, 1934 .UNITED STATES PATENT QFFIC 1 Claim.

This invention relates to an improved spark plug of the type used in connection with the present day motors of the internal combustion engine species.

It is a matter of common knowledge to those skilled in the art to which the invention relates that the spark plug art is actively developed and characterized by the incorporation therein of a multitude of different kinds and forms of spark plugs, many of which possess common characteristics.

My improved plug is also such in design and construction as to permit it to be defined as having such common characteristics as a nutequipped sectional casing and shell, a spark gap electrode, and an associated terminal contact, and an insulation body in which the electrode is mounted.

In carrying the inventive conception into actual practice, I have developed a simple and economical type of plug individualized in cornparison to prior art devices in that it possesses a new electrode arrangement, a sectional insulation body, and a two-part enclosure shell cooperable with the body in a unique and structurally distinguishable manner. y

The explicit details and particular organization thereof will become more readily apparent from the following description and drawings.

In the drawings:

Figure 1 is an elevational view of a spark plug constructed in accordance with the present invention.

Figure 2 is a central vertical sectional view therethrough.

Figure 3 is a section through the major part of the enclosure casing or shell.

Figure 4 is an elevational view of the secondary part of the insulation body.

Figure 5 is a top plan View of Figure 4.

Figure 6 is a side elevational view of the companion section of the insulation body.

Figure 7 is a plan view of Figure 6.

Figure 8 is an edge elevation of the removable screw cap of the casing.

Figure 9' is a bottom plan View of Figure 8.

I iirst call attention to Figure 3, wherein the numeral 10 designates the receptacle portion of the metallic casing. This is of appropriate proportions and conguration formed intermediate its ends on the interior with a bevelled seat 11 formed at its lower end with an externally screwthreaded attaching nipple or neck 12 formed on the exterior of its center with a nat-faced wrench grip or nut 13 and formed at its top with ex- (Cl. 12S-169) ternal screw-threads 14 to accommodate the screw cap 15.

This cap has a nut-equipped flange 16 internally screw-threaded to fit onto the threads 14. At

its center and in the flat crown portion is a screwthreaded aperture 17 forming an important factor as will be later seen. The cap also forms a closure for conning the upper end of the major insulator to be presently mentioned.

A right angular contact element is indicated by the numeral 18, this being carried by the skirt or neck portion of the receptacle 10. The numeral 19 designates the major section of the insulation body, this being either of mica lor porcelain. It embodies a cylindrical head portion 20 'iitting into the cylindrical portion of the receptacle 10, an intermediate bevelled shoulder 2l engaging the seat 11, and a cylindrical shank portion 22 extending down through an-d beyond the neck 12. This portion 22 is formed at its bottom with a depression or socket 23. Moreover the upper cylindrical head portion 20 is provided with a socket 24, the

`numeral 25 being employed to designate the lower part of the sectional electrode. At its upper end the socket 24 registers with the threaded aperture 17. Incidently the electrode extends beyond the recess 23 for co-operation with the terminal of the contact element 18. The head portion on the electrode is located in the socket 24.

The subordinate companion sections of the insulation body is generally denoted by the numeral 26 and as seen in Figure 4 this comprises a stem 27 having a threaded portion 28 tapped in through the aperture 1'7 and depending into the socket 24. The numeral 29 designates a nut and 30 represents a projected enlargement.

This section 26 is formed with a socket 3l into which the upper end portion of the upper electrode 32 extends. This electro-de 32 is co-operable with the aforesaid electrode 25 and theelectrodes may be adjusted with respect to each other to come into direct contact, or to leave a space forming a spark gap for spark intensifying action.

The numerals 33 and 34 in Figure 2 designate packing rings, the ring 33 being interposed between the upper end of the insulator section 19 and the underside of the cap 15, and the ring 34 being interposed between the surfaces 21 and 1l.

It is to be noted in this connection that bind- I l ing posts and analogous clamping means for attaching the wires to the spark plug is entirely eliminated. This simplies the arrangement and facilitates wire exchange and cleaning and repair.

The advantages claimed for the new spark plug are as follows:

(a) That the new plug embodies two separate insulators and electrodes, with an adjustable gap between the two electrodes.

(b) That by reason of the gap between the two electrodes, the new plug embodies the air-gap spark intensifying principle. Manufacturers of external air-gap spark intensifying devices for use on the usual spark plugs claim considerable advantage for this method of intensifying spark.

(c) That the air-gap spark intensifying feature is adjustable to suit the operator, thereby permitting adjustment to point of greatest efficiency for the particular motor in which it is used, or, if desired, this feature may be eliminated by bringing the two electrodes in contact with each other.

(d) That the wire from the distributor is attached to the plug by merely inserting it into the recess lin the upper insulator instead of being fastened to the plug by the usual knurled nut. No nut to become unscrewed and lost nor are any clips necessary for the end of the wire.

(e) That the diameter of the recess for the plug wire in the upper insulator will be such as to t snugly and rmly around the standard rubber-insulated plug wire, thus holding the wire firmly to the plug and at the same time, excluding moisture and dirt from the upper end of the top electrode.

(f) That by reason of the method of attaching the w-ire to the new plug, there are no exposed metal -current-carrying parts to cause electric shocks to persons coming in contact with the plug. The new plug may be safely touched and the wire may be removed and replaced while motor is running without the use of tools or fear of electric shocks.

(g) That the lower or porcelain insulator of the new plug is contained entirely within the metal body or shell and is therefore not liable to breakage by being struck by tools, etc. No brittle, easily broken porcelain parts projecting above the metal body of the new plug.

(h) 'That the upper insulator is to be made of bakelite or an insulating material less brittle than porcelain and therefore less liable to total `destruction than porcelain if accidently struck by tools, etc.

(i) That even should the upper insulator become completely destroyed, the new plug may still be used until the new part is secured, by merely removing the pieces of the broken upper 'insulator and inserting the rubber insulated plug wire through the hole in the metal cap until it makes contact with the lower electrode and wedgng it there.

(j) That the lower or porcelain insulator, being quite short and having none of its length protruding into the relatively cool air outside the motor is subject to lesser differences in temperature at its extremities and is therefore less liable to breakage due to unequal expansion.

(lc) That the metal shell body of the new plug extending outside the motor cylinder is somewhat larger than the usual construction, affording more rapid radiation to the air of heat absorbed by the plug in operation.

It will of course be understood that while the lower insulator has been referred to as porcelain and the upper insulator as Bakelite, it is not the inventors idea to limit himself to these materials and the terms are used merely to convey the idea of the general class of insulating materials used in the new plug.

It is thought that the description, taken in connection with the drawings will enable a clear understanding of the invention to be had. Therefore, a more lengthy description is thought unnecessary.

While the preferred embodiment of the invention has been shown and described, it is to be understood that minor changes coming within the eld of invention claimed may be resorted to if desired.

I claim:

A spark plug comprising a metallic shell exteriorly screw-threaded at one end for reception in a spark plug opening, a beveled shoulder within the shell, an insulator in the shell having a bevelled shoulder cooperable with the nrst mentioned bevelled shoulder, a gasket between and separating the shoulders and spacing the insulator from the shell, a cap exteriorly threaded on the outer end of the shell for cooperation with the adjacent end of the shell, a second gasket between and separating the adjacent end of the insulator and the cap and enabling forcibly holding the insulator in position in the shell and compressing the gaskets by screwing on the cap, electrode means traversing the insulator and having a portion exposed at the inward end thereof, and second electrode means on the inward end of the shell in spark-gap forming relation to the said electrode means, and supply conductor connecting means comprising an insulated body having a reduced portion adjustably threadable through an opening provided in the cap and formed in its outer end with a conductor receiving opening, conductive means traversing the insulated body and its reduced portion and exposed within the opening for contact with a supply conductor inserted therein and extending beyond the reduced portion for cooperation with an outer portion of the said electrode means in Contact and in different spark-gap forming relations.

LARA J. JONES. 

